Light-emitting Diodes (LEDs) are semiconductor devices that convert electricity into light using characteristics of compound semiconductors so as to enable transmission and reception of signals and that are used as a light source. Group III-V nitride semiconductors are highlighted as core materials of light-emitting devices, such as, e.g., LEDs or Laser Diodes (LDs) due to physical and chemical characteristics thereof. Such LEDs do not include environmentally harmful materials, for example, mercury (Hg), used in lighting appliances such as, e.g., fluorescent lamps and incandescent bulbs. Thus, LEDs are very eco-friendly and have several advantages such as, for example, long lifespans and low power consumption.
Current light sources are being rapidly replaced with LEDs. Pricing of current lighting apparatuses using light-emitting device packages, including the light-emitting device described above, and a lens provided thereon is getting more competitive. In order to reduce the price of lighting apparatuses, light-emitting device packages may need to exhibit high efficiency and have a wide viewing angle. However, recent light-emitting device packages may refract light disadvantageously and cause color deviation and luminance deviation, as well as may reflect light disadvantageously and have a narrow light distribution area.